我正在使用Jackson将JAXB带注释的对象序列化为一个地图对象。下面是一些代码来说明我的问题:如何使用Jackson将对象转换为使用默认打字的地图?
public class Test {
@XmlAccessorType(XmlAccessType.NONE)
public static class Inner {
@XmlAttribute
public int foo;
}
@XmlAccessorType(XmlAccessType.NONE)
public static class Outer {
@XmlAttribute
public String bar;
@XmlElement
public Inner in;
}
public static void main(String[] args) throws Exception {
ObjectMapper mapper = getMapper();
mapper.enableDefaultTyping();
Inner in = new Inner();
in.foo = 42;
Outer out = new Outer();
out.in = in;
out.bar = "thecakeisalie";
Object o = mapper.convertValue(out, TreeMap.class);
System.out.println(o);
}
public static ObjectMapper getMapper() {
ObjectMapper mapper = new ObjectMapper();
AnnotationIntrospector introspector = new JaxbAnnotationIntrospector();
mapper.setAnnotationIntrospector(introspector);
return mapper;
}
}
这将导致以下错误:如果线路mapper.enableDefaultTyping();
被省略,代码工作和
Exception in thread "main" java.lang.IllegalArgumentException: Unexpected token (START_OBJECT), expected START_ARRAY: need JSON Array to contain As.WRAPPER_ARRAY type information for class java.lang.Object
at [Source: N/A; line: -1, column: -1]
at org.codehaus.jackson.map.ObjectMapper._convert(ObjectMapper.java:2493)
at org.codehaus.jackson.map.ObjectMapper.convertValue(ObjectMapper.java:2459)
at com.example.test.Test.main(Test.java:49)
Caused by: org.codehaus.jackson.map.JsonMappingException: Unexpected token (START_OBJECT), expected START_ARRAY: need JSON Array to contain As.WRAPPER_ARRAY type information for class java.lang.Object
at [Source: N/A; line: -1, column: -1]
at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
at org.codehaus.jackson.map.deser.StdDeserializationContext.wrongTokenException(StdDeserializationContext.java:261)
at org.codehaus.jackson.map.jsontype.impl.AsArrayTypeDeserializer._locateTypeId(AsArrayTypeDeserializer.java:100)
at org.codehaus.jackson.map.jsontype.impl.AsArrayTypeDeserializer._deserialize(AsArrayTypeDeserializer.java:86)
at org.codehaus.jackson.map.jsontype.impl.AsArrayTypeDeserializer.deserializeTypedFromAny(AsArrayTypeDeserializer.java:69)
at org.codehaus.jackson.map.deser.std.UntypedObjectDeserializer.deserializeWithType(UntypedObjectDeserializer.java:106)
at org.codehaus.jackson.map.deser.std.MapDeserializer._readAndBind(MapDeserializer.java:321)
at org.codehaus.jackson.map.deser.std.MapDeserializer.deserialize(MapDeserializer.java:249)
at org.codehaus.jackson.map.deser.std.MapDeserializer.deserialize(MapDeserializer.java:33)
at org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:2695)
at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1308)
at org.codehaus.jackson.map.ObjectMapper._convert(ObjectMapper.java:2489)
... 2 more
输出以下:
{bar=thecakeisalie, in={foo=42}}
如果我使用映射器序列化为json,它将使用默认的键入。
默认打字与对象转换不兼容,还是我用错了?